Fabrication of a highly dispersed/active Pd nanoparticle supported catalyst: a cation-assisted reduction method in ethylene glycol–water solution at mild temperature

Development of sustainable routes to synthesize precious metal supported catalysts is of great importance because of their wide applications in the catalysis field. This paper reported a controllable and recyclable cation-assisted reduction route to fabricate a palladium nanoparticle supported catalyst. At 323 K, highly dispersed Pd/Al₂O₃-CAR_M was prepared through introducing M²⁺ (M = Mn, Zn or Cu) ions to promote the reduction of H₂PdCl₄ in ethylene glycol-water solution, and the residual filtrate after preparation could be recycled to prepare Pd/Al₂O₃ catalysts. A turnover frequency of 300 × 10² h^-1 was obtained for Pd/Al₂O₃-CAR_Mn in solvent-free aerobic oxidation of benzyl alcohol to benzaldehyde.